#
#    Licensed under the Apache License, Version 2.0 (the "License"); you may
#    not use this file except in compliance with the License. You may obtain
#    a copy of the License at
#
#         http://www.apache.org/licenses/LICENSE-2.0
#
#    Unless required by applicable law or agreed to in writing, software
#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
#    License for the specific language governing permissions and limitations
#    under the License.


def exact_filter(query, model, filters):
    """Applies exact match filtering to a query.

    Returns the updated query.  Modifies filters argument to remove
    filters consumed.

    :param query: query to apply filters to
    :param model: model object the query applies to, for IN-style
                  filtering
    :param filters: dictionary of filters; values that are lists,
                    tuples, sets, or frozensets cause an 'IN' test to
                    be performed, while exact matching ('==' operator)
                    is used for other values
    """

    filter_dict = {}
    if filters is None:
        filters = {}

    for key, value in filters.iteritems():
        if isinstance(value, (list, tuple, set, frozenset)):
            column_attr = getattr(model, key)
            query = query.filter(column_attr.in_(value))
        else:
            filter_dict[key] = value

    if filter_dict:
        query = query.filter_by(**filter_dict)

    return query
